1. Technical Field
Embodiments of the subject matter disclosed herein generally relate to methods and systems and, more particularly, to mechanisms and techniques for providing a foldable support assembly for a seismic source.
2. Discussion of the Background
During the past years, the interest in developing new oil and gas production fields has dramatically increased. However, the availability of land-based production fields is limited. Thus, the industry has now extended drilling to offshore locations, which appear to hold a vast amount of fossil fuel. Offshore drilling is an expensive process. Thus, those engaged in such a costly undertaking invest substantially in geophysical surveys in order to more accurately decide where to drill in order to avoid a dry well.
Marine seismic data acquisition and processing generate a profile (image) of the geophysical structure (subsurface) under the seafloor. This profile is used by those trained in the field, to evaluate the presence or absence of oil and/or gas traps. Thus, providing a high resolution image of the subsurface is an ongoing process for the exploration of natural resources, including, among others, oil and/or gas.
During a seismic gathering process, as shown in FIG. 1, a vessel 10 drags an array of seismic detectors provided on streamers 12. The streamers may be disposed horizontally, i.e., lying at a constant depth relative to a surface 14 of the ocean. The vessel 10 also drags a sound source assembly 16 that is configured to generate an acoustic wave 18. The acoustic wave 18 propagates downwards toward the seafloor 20 and penetrates the seafloor until eventually a reflecting structure 22 (reflector) reflects the acoustic wave. The reflected acoustic wave 24 propagates upwardly until is detected by a detector on streamer 12.
An example of a sound source assembly 16 is illustrated in FIG. 2. The sound source assembly 16 includes a float 30 that is configured to float at the surface of the water. Plural sound sources 32 are suspended from the float by cables 34 having a predetermined length. Additional cables 36 may be used to connect the plural sources 32 to each other to minimize changes in the positions of the individual sources. The plural sources 32 may be an air gun or other known devices used in the art for generating sound waves.
For creating an accurate image of the subfloor of the ocean, not only the detectors but also the sound source should comply with various requirements. For example, the positions of the plural sound sources 32 are desirable to be unchanged relative to each other after each sound generation. In addition, it was observed that having more air guns produce a more powerful source. However, for generating a desired sound wave, the plural sound sources need to be distributed along various geometrical shapes. Thus, the size of the deployed sound sources may be larger than the size of the vessel's back deck capacity, which is a challenge for storing the sound sources on the vessel and deploying the sound sources from the vessel.
Accordingly, it would be desirable to provide systems and methods that avoid the afore-described problems and drawbacks.